Grape varieties and cultivation conditions influence the bioactive polyphenols in grapes. The fox grape variety is cultivated in tropical regions and traditionally used to make grape juice. It is known to be a rich source of polyphenols, which promote health.
The researchers, who were from the Federal University of Santa Catarina in Brazil, examined the effects of short-term consumption of organic and conventional juices made from fox grapes on antioxidant biomarkers in healthy people. They hypothesized that polyphenols from tropical grape juice would improve redox homeostasis, which plays a role in fighting oxidative stress, in healthy individuals.
To test this, they asked 24 participants to drink 400 milliliters (mL) of conventional juice, organic juice, or water with a two-week washout period for every drink. The researchers took the participants’ blood samples before and one hour after consuming the drink. They analyzed these samples for reduced glutathione, total antioxidant capacity, antioxidant enzymes, blood sugar levels and uric acid levels. Reduced glutathione is the stable, active form of glutathione needed for good health.
The researchers found that those who drank both grape juices had increased reduced glutathione levels and total antioxidant capacity, as well as increased activity of antioxidant enzymes catalase, superoxide dismutase and glutathione peroxidase. Furthermore, both grape juices did not affect their glycemic status, maintaining healthy blood sugar and uric acid levels. These results demonstrated that grape juice polyphenols were associated with increased antioxidants, and there are no chemical differences between organic and conventional juices. (Related: Red wine and purple grape juice have high antioxidant activity: Study.)
The health benefits of drinking grape juice
Like red wine, which is also made from grapes, grape juice provides many health benefits. But unlike red wine, it does not contain alcohol, which makes it suitable for children. Here are several health benefits of drinking grape juice:
- It contains many nutrients – Grape juice contains vitamins B6, C and thiamine. It also provides manganese and potassium.
- It helps prevent heart attacks – Grape juice can help prevent heart attacks by lowering the risk of blood clot formation. In a study published in the journal Circulation, researchers at Georgetown University reported that drinking six 8 ounces (oz.) of grape juice can reduce the clumping of platelets that form clots in the arteries. Additionally, this can increase nitric oxide that protects the artery lining and prevents arteries from clogging.
- It lowers cholesterol – The flavonoids in grape juice help prevent the oxidation of low-density lipoprotein (LDL) or harmful cholesterol in the body – a process that can cause plaque buildup in the arteries and result in atherosclerosis.
- It strengthens the immune system – Drinking 12 oz. of grape juice for nine weeks may increase your gamma delta-T immune cells, a type of cell that detects toxins and triggers the immune system to work, according to a study in the Journal of Medicinal Food.
- It improves memory and learning – Drinking 15 to 21 oz of grape juice every day for 12 weeks may improve the memory and learning in older people, according to a study published in the British Journal of Nutrition.
Learn more about the benefits of antioxidant-rich fruits like grapes at Antioxidants.news.
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